Re-Calculating GPS – Trajectory Magazine

June 27, 2016

2016 Issue 2

By Matt Alderton

Anyone who reads the Sunday comics has probably chuckled at the antics of red-bearded, big-bellied Hägar the Horrible. Part Viking, part “everyman,” he spends his days pillaging and plundering, and his nights embroiled in quagmires that satirize both medieval and modern living. One time, for example, Hägar’s wife, Helga, chastises him for “eating like a barbarian,” then remembers that’s exactly what he is.

Thanks to caricatures like Hägar, it’s easy to stereotype Vikings as vulgar, brutish, and dim. However, Vikings were extremely astute—especially when it came to navigation. In a world without even compasses to guide them, Vikings traversed the Baltic Sea and Atlantic Ocean using nature as their only guide. By tracking the sun, moon, and stars, Vikings could determine whether they were traveling in the desired direction. And when the sky was overcast, they memorized landmarks and used migrating whales and birds as guides.

Although civilization’s most trusted navigational aide remains the sky, humanity now trusts in satellites rather than the sun. In particular, the 30 satellites that constitute the United States Global Positioning System, otherwise known as GPS.

“GPS is a worldwide enabler that is depended on by billions of users,” explained Col. Steve Whitney, director of the GPS Directorate within the Space and Missile Systems Center at U.S. Air Force Space Command, which manages and maintains the nation’s GPS capabilities. “The constellation provides a minimum of four satellites in view from any given place on the surface of the Earth to deliver sub-meter positioning accuracy to military and civil users worldwide.”

 

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